INFLUENCE OF POTASSIUM ON NITROGEN MINERALIZATION IN 2 CALCAREOUS SOILS AMENDED WITH EARTHWORM HUMUS

Two calcerous soils were amended with earthworm humus. Three potassium levels were established in the amended soils, totalizing six differen t mixtures. The nitrogen mineralization process in the mixtures was st udied. At the end of the experiment (180 days), NO3--N contents were m uch lower than those at the beginning, but NH4+-N contents were simila r (in soil B) or slightly higher (in soil A). The influence of potassi um is evident for the nitrification processes-in soil-A,. Durin the ex periment, N contents were earthworm humus were observed from one soil to another, nor for the different K levels.